Drug interactions
Foscarnet + Tacrolimus
Severity: Major
Foscarnet and Tacrolimus: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Tacrolimus can prolong the QT interval and is nephrotoxic, and foscarnet is also nephrotoxic and causes electrolyte disturbances. Combined use increases both arrhythmia risk and kidney injury risk, and renal impairment may raise tacrolimus exposure.
What this interaction means in plain words
Foscarnet and Tacrolimus can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Foscarnet belongs to Anti Virals; Tacrolimus belongs to Miscellaneous.
Why it happens
Additive QT prolongation and additive nephrotoxicity, with foscarnet-induced electrolyte depletion.
What to do
Monitor tacrolimus trough levels, serum creatinine, electrolytes and ECG closely, ensuring hydration and correcting magnesium, potassium and calcium.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Foscarnet and Tacrolimus, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
Other interactions of Foscarnet
- Cidofovir + Foscarnet Contraindicated
- Foscarnet + Pimozide Contraindicated
- Foscarnet + Thioridazine Contraindicated
- Foscarnet + Vandetanib Contraindicated
- Adagrasib + Foscarnet Major
- Adefovir + Foscarnet Major
Other interactions of Tacrolimus
- Adenovirus types 4 and 7 live + Tacrolimus Contraindicated
- Bcg vaccine live + Tacrolimus Contraindicated
- Cidofovir + Tacrolimus Contraindicated
- Cyclosporin + Tacrolimus Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Tacrolimus Contraindicated
- Measles mumps and rubella vaccine live + Tacrolimus Contraindicated
Frequently asked questions
Can I take Foscarnet with Tacrolimus?
MediHelp rates the interaction as major. Foscarnet and Tacrolimus can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Tacrolimus can prolong the QT interval and is nephrotoxic, and foscarnet is also nephrotoxic and causes electrolyte disturbances. Combined use increases both arrhythmia risk and kidney injury risk, and renal impairment may raise tacrolimus exposure.
How serious is the interaction between Foscarnet and Tacrolimus?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor tacrolimus trough levels, serum creatinine, electrolytes and ECG closely, ensuring hydration and correcting magnesium, potassium and calcium.
What other medicines interact with Foscarnet?
MediHelp also lists interactions of Foscarnet with, for example, Cidofovir, Pimozide, Thioridazine. The full list is on the Foscarnet page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
